Automatically injecting a drug (such as epinephrine, insulin, glucagon, atropine, amiodarone, dextrose, naloxone) using an autoinjector offers numerous advantages over manually injecting the drug using a manual injector. For instance, current methods of manually injecting drugs typically involve a user manually breaking an ampule holding the drug, transferring the drug from the ampule to a syringe, and then injecting the drug using the syringe. However, one example drawback of manual injection is that numerous separate components must be available to a user immediately upon need for the drug. For example, a syringe with a suitably long needle and an ampule of unexpired epinephrine must be available immediately in the event of anaphylaxis. However, in practice, it is often difficult and/or inconvenient for users to carry these items around at all times. On the other hand, an autoinjector provides a single device pre-filled with a drug and, in practice, it is easier and more convenient for a user to have a single device pre-filled with a drug compared to having the multiple components needed for manual injection.
Another example drawback of manual injection is that intramuscular injection is often difficult for an individual without medical training to execute successfully. For instance, the user must know the correct dose to administer based on the patient's weight and then translate that into the correct volume of drug solution to apply (e.g., since the drug concentrations may vary). As a result, manual injections are typically performed by a trained medical professional due to the difficulty of the manual injection. On the other hand, autoinjectors for automatically injecting a drug eliminate the need for product assembly and dosage calculation, thus making self-injection both easier and safer.
However, current autoinjectors for injecting drugs such as epinephrine have numerous drawbacks. For instance, current autoinjectors for automatically injecting epinephrine typically include drug bottles having a membrane top or pre-filled syringes. However, manufacturing autoinjectors with such drug bottles or pre-filled syringes involves aseptic manufacturing, and this increases the cost of production of the autoinjector. Further, autoinjectors with these drug bottles or pre-filled syringes are typically classified as drug/device combination and are thus subject to an expensive and time consuming regulatory approval process. This approval process in turn makes current autoinjectors typically substantially more expensive than current methods of manual injection. Furthermore, current autoinjectors are typically manufactured with a drug bottle or pre-filled syringe that is non-removable. However, since epinephrine expires after approximately 18 months, the entire autoinjector must be replaced when the epinephrine within the autoinjector expires.